GFCI Outlet

My microwave is on the counter next to the sink. It is plugged into a GFCI outlet. Several days ago while cleaning the water on the counter, my wife got a shock. The GFCI did not shut down. I immediately replaced it. Today my wife again got a shock. The outlet did shut down. I called the company. They said that the unit should shut down before getting a shock. I would appreciate any insight into this problem.

GFCI Outlet

The shock she is getting may not exceed the trip threshhold for the GFCI. Sounds like the microwave has a small current leak. When she gets the shock, where is her other hand? Is she touching something else. To get a shock, current needs to flow somewhere to complete the circuit.